If kafka truststore and keystore locations are not local files, then they
are converted to org.springframework.core.io.Resource resources, then copied
to local file system. This means that, paths can be defined as HTTP resources too.
Currently, the Kafka binder only supports CLASSPATH based resources. It would be
useful if we can support non-CLASSPATH like resources such as HTTP, so that if an
application uses config server for example to store certificates, then those will
be copied from it's HTTP endpoint to the local filesystem as Resources.
Checkstyle, documentation fixes.
Resolves https://github.com/spring-cloud/spring-cloud-stream/issues/2761
0949d4e145